<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin:0;
            padding:0;
        }
        ul li{
            cursor:pointer;
        }
        #id_close{
            cursor:pointer;
        }
    </style>
</head>
<body style="width:100%;height:100%;padding:10px;">
<!-- 主视图区域 -->
    <div style="float: left; width:200px;;height:100%padding:10px;border:1px solid yellow;">
        <a id="id_close">关闭</a>
        <ul id="tree" style="background-color:blueviolet;">
     
        </ul>

    </div>
    <div id="pid"  style="float: left;width:60%;height:100%;background:#eefe;padding:10px;border:1px solid green;"></div>
    <div style="float:left; width:20%;height:100%;background:#eefe;padding:10px;border:1px solid indianred;"></div>

</body>
</html>